1. Field of the Invention
The present invention relates to an imprint apparatus, a method of manufacture configured for an article using the same, and an imprint method.
2. Description of the Related Art
In addition to conventional lithography techniques, increasing demand for the miniaturization of semiconductor devices, MEMS, or the like, has focused attention on miniaturization processing techniques in which an uncured resin is formed using a die (mold) on a substrate and a resin pattern is formed on the substrate. These techniques are termed imprint techniques, and enable the formation on the substrate of a miniaturized structure on the order of several nanometers. Photocuring methods are one example of an imprint technique. An imprint apparatus that employs a photocuring method first coats an ultraviolet curable resin (e.g., an imprint material, or a photocurable resin) on a shot that is an imprint region on the substrate (for example, a wafer). Next, the resin (uncured resin) is formed using a mold. A resin pattern is formed on the substrate by release after irradiation with UV radiation to cure the resin. Since the imprint technique according to this type of photocuring method can control the temperature in a relatively simple manner and enable detection of an alignment mark formed on the substrate through a transparent mold, it is particularly adapted to the manufacture of a semiconductor device.
When executing an imprint process with the imprint apparatus employing the above technique, an alignment process of the mold and the substrate is performed in the same manner as a general exposure apparatus, or the like, and the shape of the pattern portion formed on the mold and the pattern on the substrate side that is pre-formed on the shot are aligned. A method of alignment processing includes, for example, die-by-die alignment or global alignment. A method of die-by-die alignment performs optical detection of a mark formed on a shot for each shot on a substrate and then performs a correction for a deviation in the positional relationship between the original plate (mold or reticle in an exposure device) and the substrate. On the other hand, a global alignment method uses the fact that the positional relationship between the apparatus and the substrate, or the apparatus and the original plate is clear, and corrects a deviation based on an index that is obtained by performing statistical processing of the detection results in relation to a mark formed on a number of representative shots (sample shots). In other words, the global alignment method executes the alignment process using the same index with respect to all shots. In a conventional exposure apparatus, the global alignment method is generally used from the point of view of improving throughput.
In this context, a conventional exposure apparatus corrects a deviation due to a change in the shape of each shot during an exposure process by changing the reduction magnification of the projection optical system in accordance with the shape (magnification) of the shot, or by changing the scanning speed of the substrate stage. However, an imprint apparatus does not include a projection optical system and cannot execute this type of shot correction (magnification correction) due to direct contact between the resin on the substrate and the mold. Therefore, the imprint apparatus employs a magnification correcting mechanism that holds the mold with a holding unit (chuck) operating due to mechanical fixture or vacuum suction, or the like, and executes expansion by application of an external force from the side face of the mold or by heating the mold to thereby physically deform the mold. Japanese Patent Laid-Open No. 2007-535121 discloses an imprint system that is configured to deform a mold by application of an external force by use of an actuator, or the like, to thereby deform the shape of a pattern portion relative to the pattern on the substrate side.
However, since the conventional imprint apparatus executes constant fixed retention of the mold using the holding unit, as described above, even when an external force is applied to the mold, as described in Japanese Patent Laid-Open No. 2007-535121, in order to deform the shape of the pattern portion, the mold resists deformation. In this regard, when an external force is applied after simply temporarily removing the fixed retention of the mold in order to improve the deformation efficiency, the retention position itself of the mold undergoes a change. Therefore, when employing a global alignment method as the method for alignment processing, the value measured in relation to alignment processing can no longer be used for reference due to the fact that the mold has deviated after execution of the alignment processing.